September is 5.7ºF warmer than average as of the 20th, so it would be nice to start seeing some Fall-like weather (or even just a reduction in the excessive heat) for the first day of astronomical Fall on Saturday.
The Autumnal Equinox occurs at 8:54 PM Saturday; that’s the moment the Sun is directly overhead at the Equator. For us, it means that the Sun is lower in the sky than it was at it’s highest on June 21st; that also means the heat cannot last much longer. We don’t see any ‘cool’ air coming this weekend, but temperatures will drop some because of clouds, shower and thunderstorms in the area. Expect highs in the upper 80s and lower 90s, and any of the spotty downpours that develop could get heavy in a hurry. In other words, the lower-end 30% chance of rain says nothing about how hard the rain could get!
What’s the Autumnal Equinox? The equinox means ‘equal nights.’ It’s one of two points in the year in which the Sun’s celestial path crosses the Equator. The Sun doesn’t actually move – we do.
Because of the Earth’s tilt, the Sun’s position in our sky changes as we revolve around the Sun throughout the year.
On September 22nd, the Sun’s rays will be directly over the Equator as the Sun’s celestial path moves farther toward and into the Southern Hemisphere (which will be pointing more and more toward the Sun over the next few months).
That means the sun angle gets lower and the days get shorter around here through December 21st.
By the way ‘Equinox’ is taken from a Latin word meaning ‘equal nights.’ We don’t have equal day and night all over the world on the Equinox, but it’s close.
North Alabama has exactly 12 hours between sunrise and sunset on September 26th: four days after the Equinox.
A real cool down? Sweater weather? Not likely. More comfortable, more like late September or early October should be? Yeah, that’s about the size of it.
We see a very good chance of ‘cooler’ weather within the next 10-15 days. Most of next week will still be warmer than the average for this time of year, but it won’t feel like a blast furnace as this past week has! Temperatures trend downward because of showers and thunderstorms in the area through most of next week, and then a real, legitimate cold front moves in next Friday allowing for the most comfortable weather in months.
So what does this cool down look like? The Climate Prediction Center’s 8-14 Day outlook shows a 30-40% chance of below-average temps between September 28th and October 4th. Here’s that outlook and a graph showing our forecast plus some model guidance that really takes a bite out of the heat by September 29th!
You’d have to go back about 143 days (almost five full months) to see weather as nice as we expect by next weekend. It’s possible, but it’s not here yet! No one would blame you at all for taking an “I’ll believe it when I see it” kind of attitude!